The fact you're not leaving personal items in the common area does sort of indicate that the bits he's visiting are simply basic facilities provided for you to use. It is your room that you're renting and can expect to have quiet enjoyment of.
The text messages could well be excessive, especially over the trivial stuff - but are you exaggerating a bit there re: "most days of the week?"
I mean if you are literally getting a text message off him 4 or more days a week then that does seem rather needless and worth having a word with him about.
I thought as much, re: room vs communal area.
Sadly I'm not exaggerating, we receive 4-5 messages a week about the house. Some of it is needed, ie letting us know about maintenance issues etc, the rest is just moaning about trivial things. The latest was threatening to charge us if a significant other stayed overnight at the house for more than 2 nights a month and demanding that we seek "approval" with 48 hours notice.